Numerous devices and methods exist for locking a vehicle steering column from movement or for otherwise rendering the steering structure of a vehicle unusable. Most commonly, such devices and methods prevent the steering column from being rotated to steer the vehicle. The vehicle can be a car, van, truck, motorcycle, bus, or all-terrain vehicle having a number of wheels, a boat with one or more rudders, a snowmobile with skis, any vehicle having one or more tracks, and the like. A steering column lock used in any such vehicle is typically employed to prevent vehicle theft or unauthorized use.
A popular and well-known mechanism for locking a steering column is a lock bolt that is directly or indirectly releasably engagable with the steering column. Such engagement can be by removable insertion of the lock bolt into a groove, a notch, teeth, or other aperture or feature in the steering column or in a gear, plate, or other element connected to the steering column. Also, the lock bolt can be spring-biased into a locking position in a number of different manners. A mechanism is normally provided for retracting the lock bolt from the steering column (whether against spring-loaded force or otherwise) for vehicle operation. As is well known to those skilled in the art, the mechanism can retract the lock bolt in response to user insertion and turning of a key or in response to one or more signals from a control system coupled to an actuator driving the mechanism.
A familiar problem with many conventional steering column locks is the ability of the lock bolt to be retracted from its locked position while torque is exerted upon the steering column. Such a force can bind the lock bolt to prevent or resist retraction of the lock bolt from its locked position, and can present retraction problems regardless of whether the lock bolt is retracted by mechanical force from turning a key or by an actuator driving the lock bolt as described above. For example, after the lock bolt has been extended to a locked position into a groove, notch, or other aperture as described above, a turning force from the front wheels can bind the lock bolt in this position. In many cases, the user must turn the steering wheel to release the binding force upon the lock bolt in order to turn the ignition key, retract the lock bolt, and thereby unlock the steering column.
While lock bolt binding is not necessarily a critical design flaw in conventional manually-actuated steering column locks, it can present greater problems in newer steering column locks that are not mechanically connected to an ignition lock cylinder for actuation thereby. For example, with the introduction in recent years of vehicle security systems in which a steering column lock is locked and unlocked by an electronic controller connected to one or more steering column lock actuators, there is little need to locate a vehicle's ignition control (e.g., switch, button, and the like) adjacent to the steering column lock. The ignition control can be directly or indirectly connected to the steering column lock by wiring alone, and therefore can be located almost anywhere in the vehicle. Also, in some cases the steering column lock need not necessarily be responsive to the ignition control of the vehicle, but can instead be responsive to a lock controller operable independently of the vehicle's ignition control. However, without the ability of a user to mechanically manipulate the lock bolt as in most older steering column lock designs described above, reliable lock bolt disengagement can be a significant problem, particularly when the lock bolt is subjected to binding forces.
In light of the problems and limitations of conventional steering column locks, new steering column lock designs would be welcome in the art.